Social search engine Sproose—which features user-driven search result relevancy—launches this morning. Sproose users vote on the web sites that appear in search results, and Sproose ranks the highest voted before less popular pages in future searches. In other words, as more and more people vote for pages that fit a specific search result, those results will have a greater likeliness to appear on the top of Sproose's search results. Here's a screenshot of a more active search on Sproose:

Lesser ranked entries appear lower down on the list. Right now Sproose needs more registered voters to balance out any attempts at manipulating the search results, but overall looks like a promising Google-Digg hybrid.